Multi-rate optical disc recording and reproducing apparatus

ABSTRACT

Multi-rate optical disc recording method and apparatus wherein data are recorded on the optical disc in accordance with a transfer rate of data, thereby preventing an unnecessary waste of a storage area in the optical disc and also enhancing a recording time of the optical disc. Said method and apparatus exploit a transfer rate detector for detecting a transfer rate of a digital signal generated at a digital signal source. This transfer rate detector allows a rotation velocity controller to rotate the optical disc at a speed corresponding to the transfer rate of the digital signal, in response to the transfer rate of the detected digital signal. Also, the transfer rate detector allows a recording portion to record the digital signal on the optical disc at the detected transfer rate.

This application is a continuation-in-part of application Ser. No.08/752,037 filed on Nov. 19, 1996 now U.S. Pat. No. 5,982,726, theentire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an optical disc recording and reproducingapparatus that optically accesses the optical disc, and moreparticularly recording method and apparatus of a multi-rate optical discwherein the optical disc can be adaptively driven based on a transferrate of data to be recorded.

2. Description of the Prior Art

In a conventional optical disc recording and reproducing apparatus,light beams are irradiated onto the optical disc such as CompactDisc(CD) and Digital Versatile (or Video) disc (DVD) in order to accessdata. Such optical discs record binary data representing audio signals,video signals, text information, etc.

Digital signals recorded onto the optical disc and reproduced therefrominclude various recording signals such as a video signal, an audiosignal, digital data or a digital broadcasting program including acombination of all of said signals, etc. Each of these signals has adifferent data quantity, for example digital bit quantity per second,respectively. Also, in the same broadcasting program, the data quantityis different according to the attribute of a broadcasted program.Specifically, the data quantity is about 6 to 7 Mbps in the case of asports program, whereas the data quantity is generally about 3 to 4 Mbpsin the case of a movie program. Moreover, the data quantity may differaccording to the number of pixels of a program being provided.Specifically, the data quantity is about 5 to 6 Mbps in the case of theexisted NTST and PAL signals having an array of about 720×480 pixels(normal video signal hereinafter), whereas the data quantity isgenerally about 10 to 15 Mbps in the case of a high density signalhaving an array of 1024×1024 pixels (high resolution signalhereinafter). Optical disc apparatuses must therefore be capable ofrecording and reproducing digital programs having such various dataquantities.

However, a conventional optical disc has only a single-rate recordingmeans. The following is a description of an example of a conventionaloptical disc recording and reproducing apparatus, which records andreproduces the normal video signal of 5 Mbps and the high resolutionsignal of 10 Mbps to/from a conventional optical disc. The conventionaloptical disc recording and reproducing apparatus drives the optical discat a transfer rate of 10 Mbps on the optical disc. Consequently, whenrecording the high resolution video signal of 10 Mbps in a real time,the conventional optical disc recording and reproducing apparatus canexploit the entire recording area of the optical disc, that is, 100% ofrecording area in the optical disc. By contrast, when recording thenormal video signal of 5 Mbps in real time, the conventional opticaldisc recording and reproducing apparatus wastes half the record area,that is, 50% of record area in the optical disc unnecessarily. Such aconventional optical disc recording and reproducing apparatus alsowastes the recording area unnecessarily when recording the audio signaland the text signal with different transfer rates.

For reference, the following describes the process in which the highresolution video signal and the normal video signal are recordedrespectively, using the optical disc recording and reproducingapparatus.

FIG. 1 is a time chart for explaining the process in which the highresolution video signal of 10 Mbps is recorded by the optical discrecording and reproducing apparatus. The frame dividing signal FDS shownin FIG. 1 assigns odd number and even number frames of the video signal.The high logic region and the low logic region of the frame dividingsignal FDS represent the odd number frames and the even number frames,respectively. The high resolution video data divided into frame unitsaccording to this frame dividing signal is inputted to optical discrecording and reproducing apparatus at a rate of 10 Mbps. Then, theoptical disc recording and reproducing apparatus formats the highresolution video signal HVD in a certain form required by an opticaldisc, and records on the optical disc. At this time, the optical disc isrotated at a constant velocity by the optical disc recording andreproducing apparatus like DSS shown in FIG. 1. As a result of this, aninformation pit train IPT is formed on the information track of theoptical disc having frame video data pits arranged continuously, asshown in FIG. 1.

FIG. 2 is a time chart for explaining the process in which the normalresolution video signal of 5 Mbps is recorded by the optical discrecording and reproducing apparatus. In FIG. 2, the normal video dataNVD are divided into frame units by the frame dividing signal FDS. Thisnormal video data is inputted to the optical disc recording andreproducing apparatus at a transfer rate of 5 Mbps, and formatted, likeFNVD in FIG. 2, by the optical disc recording and reproducing apparatus.The formatted normal video data FNVD consists of compressed frame videodata and null data inserted between the compressed frame video data.These null data are generated because the normal video data NVD of 5Mbps is temporally compressed into ½ by the optical disc recording andreproducing apparatus operating at a rate of 10 Mbps. In turn, theformatted normal video data FNVD are recorded on the optical disc usingthe optical recording and reproducing apparatus. At this time, theoptical disc rotates at the same velocity used to record the highresolution video data. As a result of this, an information pit train IPTis formed on the information track of optical disc in which video datapit regions, and null data pit regions are arranged alternately.

As described above, the conventional optical disc recording andreproducing apparatus causes the null data to be recorded on opticaldisc because it records data on the optical disc at a fixed transferrate, regardless of the transfer rate of data. The conventional opticaldisc recording and reproducing apparatus therefore wastes the recordingarea of the optical disc unnecessarily.

SUMMARY OF THE INVENTION

An object of the present invention is to provide multi-rate optical discrecording method and apparatus which can prevent the unnecessary wasteof the storage area of optical disc by recording data on the opticaldisc in response to the transfer rate of data.

In order to obtain the above object, a multi-rate optical disc recordingmethod according to one aspect of the present invention comprises stepsof detecting a transfer rate of the digital signal, controlling arotation velocity of the optical disc in accordance with the transferrate of the digital signal, and recording the digital signal on theoptical disc.

A multi-rate optical disc recording method according to another aspectof the invention comprises steps of setting a recording speed of thedigital signal, controlling a rotation velocity of the optical disc inaccordance with the recording speed, converting a transfer rate of thedigital signal in accordance with said recording speed, and recordingthe converted digital signal on the optical disc.

A multi-rate optical disc recording method according to another aspectof the invention, in an optical disc recording apparatus for accessingan optical disc optically, comprises steps of detecting a transfer rateof a first digital signal generated from a digital signal source,rotating the optical disc at a speed corresponding to the transfer rateof the first digital signal, deciding whether a second digital signalwas recorded on the optical disc or not, and recording the first digitalsignal from a final position of the second digital signal in the opticaldisc.

A multi-rate optical disc recording method according to still anotheraspect of the invention, in an optical disc recording apparatusincluding an optical pick-up for accessing a spiral information track onan optical disc optically, comprises steps of detecting a transfer rateof a first digital signal generated from a digital signal source,rotating the optical disc at a speed corresponding to a transfer rate ofthe first digital signal, deciding whether a second digital signal wasrecorded on the optical disc or not, comparing whether a transfer rateof the second digital signal is identical to that of the first digitalsignal, changing a rotation velocity of the optical disc into a speedcorresponding to the transfer rate of the second digital signal,detecting a final position of the second digital signal on theinformation track and information about the final position, changing therotation velocity of the optical disc into the speed corresponding tothe transfer rate of said first digital signal, waiting until therotation velocity of the optical disc arrives at the speed correspondingto the transfer rate of the first digital signal, jumping reversely theoptical pick-up into a position prior to the final position of thesecond digital signal, and applying the first digital signal to theoptical pick-up to record it on the optical disc.

Further, a multi-rate optical disc recording apparatus according to oneaspect of the present invention comprises means for detecting a transferrate of a digital signal from a digital signal source, optical discdriving means for rotating the optical disc in response to the transferrate of the digital signal detected by the transfer rate detectingmeans, and means for recording the digital signal on the optical disc atthe transfer rate detected by the transfer rate detecting means.

A multi-rate optical disc recording apparatus according to other aspectof the present invention comprises means for recording a digital signalfrom a digital signal source on an optical disc, record mode determiningmeans for a recording speed of the digital signal, and means forcontrolling a rotation velocity of the optical disc in response to therecording speed determined by the record mode determining means.

A multi-rate optical disc recording apparatus according to anotheraspect of the present invention comprises means for detecting a transferrate of a digital signal from a digital signal source, optical discdriving means for rotating the optical disc in response to the transferrate of the digital signal detected by the transfer rate detectingmeans, and means for recording the digital signal on the optical disc atthe transfer rate detected by the transfer rate detecting means.

A multi-rate optical disc recording apparatus according to still anotheraspect of the present invention comprises means for detecting a transferrate of a digital signal from a digital signal source, buffer means forstoring the digital signal from the digital signal source temporarily,variable clock generating means for generating a clock signal ofvariable frequency, disc driving means for rotating the optical disc,means for recording a digital signal stored in the buffer means on theoptical disc in response to the clock signal from the variable clockgenerating means, and means for controlling the variable clockgenerating means and the disc driving means in response to the transferrate detected by the transfer rate detecting means to control afrequency of the clock signal and a rotation velocity of the opticaldisc.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects of the invention will become apparent from thefollowing detailed description of the embodiments of the presentinvention with reference to the accompanying drawings, in which:

FIG. 1 shows a timing chart for explaining the process in which the highresolution video data are recorded on the optical disc by theconventional optical disc recording and reproducing apparatus.

FIG. 2 shows a timing chart for explaining the process in which thenormal video data are recorded on the optical disc by the conventionaloptical disc recording and reproducing apparatus.

FIG. 3 is a block diagram of an optical disc recording and reproducingapparatus according to the preferred embodiment of the presentinvention.

FIG. 4 shows output waveforms corresponding to parts of the optical discrecording and reproducing apparatus in FIG. 3.

FIG. 5 provides a detailed illustration of the data format of the framevideo data shown in FIG. 4.

FIG. 6 is a flow chart for explaining a multi-rate recording methodaccording to the first embodiment of the present invention.

FIG. 7 is a flow chart for explaining a multi-rate recording methodaccording to the second embodiment of the present invention.

FIG. 8 is a diagram for explaining a recording start position of theoptical disc and a pattern of the frame data pit train according to themulti-rate recording method in the second embodiment of the invention.

FIG. 9 is a flow chart for explaining a multi-rate recording methodaccording to the third embodiment of the present invention.

FIG. 10 is a diagram for explaining a recording start position of theoptical disc and a pattern of the frame data pit train according to themulti-rate recording method in the third embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 3, there is shown an optical disc recording andreproducing apparatus according to the preferred embodiment of thepresent invention which comprises a transfer rate detector 10 and abuffer 12 commonly connected to an input/output line 11. Theinput/output line 11 is connected to a data source (not shown) in orderto transfer the video data VDS from the data source into the buffer 12or to transfer the video data VDS from the buffer 12 into the datasource. This video data VDS is transferred in the shape of a frame unit,as shown in FIG. 5 according to the frame dividing signal FDS. The framevideo data consists of only data portions including information aboutpixels, or of both identification code portions including informationabout a transfer rate and data portions including information aboutpixels. The video data is classified into high resolution video data HVDand normal video data NVD in accordance with the number of pixels. Thehigh resolution video data HVD is formed by formatting an array of1024×1024 pixel data to one frame and making a moving picturecompression of the formatted frame video data, which are transferred ata transfer rate of 10 Mbps. The normal video data NVD is formed byformatting an array of 325×525 pixel data to one frame, which istransferred at a transfer rate of 5 Mbps. The transfer rate detector 10detects a transfer rate value of video data VDS from the identificationportion included in the video data VDS from the input/output line 11.The transfer rate value is detected by the transfer rate detector 10only when the identification code portion is included in the video dataVDS. The buffer 12 temporarily stores the video data VDS inputted fromthe input/output line 11 and the reproduced video data to be transferredtoward the input/output line 11. The buffer 12 has enough storagecapacity to store two frame video data.

The optical disc recording and reproducing apparatus further comprises akey input portion 14 for sending an instruction assigned by a user viathe first node 13 to microcomputer 16, a clock frequency change portion18 connected to the microcomputer 16, and a rotational velocity controlportion 20. The key input portion 14 inputs recording, reproducing andretrieval instructions from a user as well as virtual addresses intendedto record and reproduce, and supplies the inputted instructions andaddresses to the microcomputer 16 via the first node 13. Also, duringrecording, the key input portion 14 inputs a transfer rate value relatedto the data to be recorded, and supplies the transfer rate value to themicrocomputer 16. For this purpose, the key input portion 14 includeskey switches (not shown) and/or a keyboard.

In the recording mode, the microcomputer 16 generates clock frequencydata and rotational velocity data in accordance with a transfer ratevalue inputted via the second node 15 from the transfer rate detector10. Also, the microcomputer 16 generates the clock frequency data andthe rotational velocity data corresponding to the transfer rate valuefrom the key input portion 14 when the transfer rate value is notdetected by the transfer rate detector 10. The clock frequency data issupplied to the clock frequency change portion 18 via the third node 17,and the rotational velocity data is supplied to the rotation velocitycontrol portion 20 via the fourth node 19.

The clock frequency change portion 18 varies the frequency of the clocksignal generated at a clock generator 22 in accordance with a logicvalue of the clock frequency data applied via the third node 17 from themicrocomputer 16. The clock generator 22 generates the first clocksignal FCS or the second clock signal SCS under control of the clockfrequency change portion 18. The first clock signal FCS is generatedwhen the video data VDS is inputted to the input/output line 11 at atransfer rate of 5 Mbps, which has a frequency of 5 MHz. For this, theclock generator 2 includes a voltage controlled oscillator (not shown),and the clock frequency change portion 18 includes a decoder (not shown)such as a digital-to-analog converter.

On the other hand, the rotational velocity control portion 20 rotates aspindle motor 14 at a speed corresponding to the rotational velocitydata inputted via the fourth node 19 from the microcomputer 16. Forexample, the rotational velocity control portion 20, like DSV in FIG. 4,rotates the spindle motor 24 at a speed of 100 rps when the highresolution video data HVD of 10 Mbps is inputted to the input/outputline 11. By contrast, rotational velocity control portion 20 rotates thespindle motor 24 at a speed of 50 rps when the normal video data NVD isinputted to the input/output line 11. In response to rotation of thespindle motor 24, the optical disc D is subject to rotate at a samevelocity as the spindle motor 24.

Furthermore, the optical disc recording and reproducing apparatuscomprises a formatter 26 connected in serial with the buffer 12, adigital signal processor 28 (DSP hereinafter), and a channel modem 30.The formatter 26 formats the video data VDS from the buffer 12 into apattern required by an optical disc D and, at the same time, applies theformatted video data to the buffer 12. Also, the formatter 26 reverselyformats the reproduced video data from the DSP 28 into the originalpattern and applies the reversely formatted video data to the buffer 12.The formatter 26 inputs the video data VDS stored in the buffer 12 at arate of 10 Mbps or 5 Mbps in accordance with the clock signal from theclock generator 22. Specifically, the formatter 26 inputs the video dataVDS from the buffer 12 at a rate of 10 Mbps when the first clock signalFCS is applied from the clock generator 22, while it inputs the videodata VDS from the buffer 12 at a rate of 5 Mbps when the second clocksignal SCS is applied from the clock generator 22.

Under control of the microcomputer 16, DSP 28 converts the video datafrom the formatter 26 into the form of a data bit stream or restores thevideo data from the reproduced data bit stream. Specifically, in therecording mode, DSP 28 detects a synchronous pattern and an address froma support signal demodulated from the channel modem 30, and supplies thedetected synchronous pattern and address to the microcomputer 16. Also,DSP 28 converts the formatted video data from the formatter 26 into theform of a data bit stream. This data bit stream is to be added by anerror correction code, an address and a synchronous pattern besides thevideo data, which is supplied to the channel modem 30. The supportsignal is a signal which is preformatted on the track in the opticaldisc, and includes a synchronous pattern indicating the rotationalvelocity of the optical disc D and an address indicating the physicalposition of the storage area.

In the reproduction mode, DSP 28 separates video data, an errorcorrection code, a synchronous pattern and an address from thereproduced data bit stream from the channel modem 30, and corrects anerror generated in the video data by the error correction code. Also,DSP 28 applies the error corrected video data to the formatter 26 andsupplies the synchronous pattern and the address to the microcomputer16.

In the recording mode, the channel modem 30 channel-codes a data bitstream to be recorded from the DSP 28, and channel-decodes a supportsignal reproduced from the optical disc D and received throughreproducing portion 36 and optical pick-up 32. The channel-decodedsupport signal is applied to the DSP 28. In the reproduction mode, thechannel modem 30 channel-decodes a data bit stream reproduced from theoptical disc and supplies the channel-decoded data bit stream to DSP 28.

The optical disc recording and reproducing apparatus further comprisesan optical pick-up device 32 for accessing the optical disc D optically,and a recording portion 34 and a reproducing portion 36, which areconnected between the channel modem 30 and the optical pick-up device32. Under control of the microcomputer 16, the optical pick-up device 32moves back and forth in a radial direction of the optical disc to recorddata on the track in the optical disc D or pick-up information recordedon the track in the optical disc D. For this purpose, the opticalpick-up device 32 irradiates a relatively large energy of light beamonto the surface of the optical disc D in the recording mode. Bycontrast, it radiates a relatively small energy of light beam onto thesurface of the optical disc D in the reproduction mode.

The recording portion 34 allows a light beam irradiated on the track inthe optical disc D to be switched by controlling the optical pick-updevice 32 in accordance with the data bit stream from the channel modem30. As a result, a data pit train WDP indicating “1” or “0” inaccordance with the data bit stream is formed in such a manner that aspiral track is shaped in the optical disc D.

In this data pit train WDP, HVDP represents the data pit train relativeto one frame of high resolution video data and NVDP does the data pittrain relative to one frame of normal video data.

The reproducing portion 36 processes a high frequency signal from theoptical pick-up device 32 to generate a support signal and a data bitstream from the high frequency signal. The support signal and the databit stream generated at the reproducing portion 36 are supplied to thechannel modem 30.

FIG. 6 is a flow chart for explaining a multi-rate recording methodaccording to the first embodiment of the present invention. The processin FIG. 6 is performed by the microcomputer 16 (shown in FIG. 3).

Referring now to FIG. 6, in step 40, the microcomputer 16 waits until arecord instruction is inputted from the key input portion 14. If therecord instruction is inputted in step 40, then the microcomputer 16sets a record mode flag assigned in a part of register therein, andinputs a transfer rate value of video data from the transfer ratedetector 10 (step 42).

In step 44, the microcomputer 16 decides, based on the transfer ratevalue, if the video data VDS on the input/output line is high resolutionvideo data HVD or normal video data NVD. When the transfer rate value is10 Mbps, the microcomputer 16 decides that the high resolution videodata HVD is being applied to the input/output line 11. When the transferrate value is 5 Mbps, the microcomputer 16 decides that the normal videodata NVD is being applied to the input/output line 11.

If it is decided that the high resolution video data HVD is applied tothe input/output line 11 in step 44, then the microcomputer 16 allowsthe clock generator 22 to generate the first clock signal FCS of 10 MHzby controlling the clock generator 22 via the clock frequency changeportion 18 (step 46). At this time, the formatter 26 inputs the highresolution video data HVD in the buffer 12 at a rate of 10 Mbps, bymeans of the first clock signal from the clock generator 22. As aresult, the high resolution video data HVD recorded on the optical discD is transferred at a rate of 10 Mbps by way of the formatter 26, theDSP 28, the channel modem 30, the recording portion 34 and the opticalpick-up device 32. Subsequently, the microcomputer 16 allows therotational velocity controller 20 to rotate the spindle motor 24 at aspeed of 100 rps by controlling the rotational velocity controller 20(step 48). In response to a rotation of the spindle motor 24 at thespeed of 100 rps, the optical disc D also is subject to rotate at aspeed of 100 rps.

On the other hand, if it is decided that the normal video data NVD isapplied to the input/output line 11 in step 44, then the microcomputer16 allows the clock generator 22 to generate the second clock signal SCSof 5 MHz by controlling the clock generator 22 via the clock frequencychange portion 18 (step 50). At this time, the formatter 26 inputs thenormal video data NVD in the buffer 12 at a rate of 5 Mbps, by means ofthe second clock signal from the clock generator 22. As a result, thenormal video data NVD recorded on the optical disc D is transferred at arate of 5 Mbps by way of the formatter 26, the DSP 28, the channel modem30, the recording portion 34 and the optical pick-up device 32.Subsequently, the microcomputer 16 allows the rotational velocitycontroller 20 to rotate the spindle motor 24 at a speed of 50 rps bycontrolling the rotational velocity controller 20 (step 52). In responseto a rotation of the spindle motor 24 at the speed of 50 rps, theoptical disc D also is subject to rotate at a speed of 50 rps.

After performing the above steps 46-48 or 50-52, the microcomputer 16controls the optical pick-up device 32 by allowing the optical pick-updevice 32 to record the data bit stream from the channel modem 30 on theoptical disc D (step 54). As a result, an appropriate frame data pittrain, such as HVDP or NVDP in FIG. 4, is generated in the optical discD. Herein, HVDP represents a data pit train relative to one frame ofhigh resolution video data, and NVDP represents a data pit trainrelative to one frame of normal video data.

FIG. 7 is a flow chart for explaining a multi-rate recording methodaccording to the second embodiment of the present invention. The processin FIG. 7 is performed by the microcomputer 16 (shown in FIG. 3).

Referring now to FIG. 7, in step 56, the microcomputer 16 waits until arecord instruction is inputted from the key input portion 14. If therecord instruction is inputted in step 56, then the microcomputer 16sets a record mode flag assigned in a part of register therein, andinputs a transfer rate value of video data from the transfer ratedetector 10 (step 58).

In step 60, the microcomputer 16 decides, based on the transfer ratevalue, if the video data VDS on the input/output line 11 is highresolution video data HVD or normal video data NVD. When the transferrate value is 10 Mbps, the microcomputer 16 decides that the highresolution video data HVD is being applied to the input/output line 11.When the transfer rate value is 5 Mbps the microcomputer 16 decides thatthe normal video data NVD is being applied to the input/output line 11.

If it is decided that the high resolution video data HVD is applied tothe input/output line 11 in step 60, then the microcomputer 16 sets thefirst recording speed mode flag assigned in a part of register therein,specifying that the data is to be recorded at a rate of 10 Mbps (step62). On the other hand, if it is decided that the normal video data NVDis applied to the input/output line 11 in step 60, then themicrocomputer 16 sets the second recording speed mode flag assigned in apart of register therein instead of the first recording speed mode flag,specifying that the data is to be recorded at a rate of 5 Mbps (step64).

After performing the above step 62 or 64, the microcomputer 16 controlsthe spindle motor 24 via the rotational velocity controller 20 such thatthe spindle motor 24 rotates at a rate corresponding to the recordingspeed mode set in step 62 or 64. At the same time, the microcomputer 16retrieves a table on the lead-in area of optical disc D inputted by wayof the optical pick-up device 32, the recording portion 36, channelmodem 30 and the DSP 28, and decides whether there are a previouslyrecorded video data or not (step 66). When a start address and an endaddress exist in the table, the microcomputer 16 decides that previouslyrecorded data exists in the optical disc D. Otherwise, when an startaddress and an end address data do not exist in the retrieved table, themicrocomputer 16 decides that previously recorded data does not exist inthe optical disc D. The spindle motor 24 rotates at a rate of 100 rpswhen the first recording speed mode is set in step 62 while rotating ata rate of 50 rps when the second recording speed mode is set in step 64.

In step 66, if there is data recorded previously in the optical disc,then the microcomputer 16 compares a logical value of the recordingspeed mode flag with that of the transfer speed mode flag on the table,and decides whether the recording speed mode of the previously recordeddata is identical to that of the data to be recorded (step 68). If thelogical value of the recording speed mode flag is not identical to thatof the transfer speed mode flag, it is judged that the recording speedmode of the previously recorded data is different from that of the videodata to be recorded.

When the recording speed mode of the previously recorded data isdifferent from that of the video data to be recorded in step 68, themicrocomputer 16 allows the spindle motor 24 to be rotated at a speedcorresponding to the recording speed mode of the previously recordeddata by controlling the spindle motor 24 via the rotation velocitycontroller 20. The final portion of the recording region is then soughtbased on whether data is inputted from the DSP 28, making a track jumpof the optical pick-up device 32 if necessary (step 70). At this time,if the first recording speed mode was set in step 62, the spindle motor24 rotates at a speed of 50 rps; whereas if the second recording speedmode was set in step 64, the spindle motor 24 rotates at a speed of 100rps. Further, the microcomputer 16 allows the clock generator 22 tosupply a clock signal to the formatter 26 having a frequencycorresponding to the recording speed mode by controlling the clockgenerator 22 via the clock frequency change portion 18 (step 72). Forexample, when the first recording speed mode is set in step 62, theclock generator 22 applies the first clock signal FCS to the formatter26. Accordingly, the high resolution video data on the input/output line11 is delivered to the optical pick-up device 32 at a transfer rate of10 Mbps via the buffer 12, the formatter 26, the DSP 28, the channelmodem 30 and the recording portion 34 in turn. Otherwise, when thesecond recording speed mode is set in step 64, the clock generator 22applies the second clock signal SCS to the formatter 26. Thus, thenormal video data NVD on the input/output line 11 is transferred at atransfer rate of 5 Mbps via the buffer 12, the formatter 26, the DSP 28,the channel modem 30 and the recording portion 34 in turn into theoptical pick-up device 32. The microcomputer 16 allows the spindle motor24 to rotate at a speed corresponding to the recording speed mode set instep 62 or 64 by controlling the spindle motor 24 via the rotationvelocity controller 20 (step 74), and then it waits until the rotationspeed of the spindle motor 24 maintains a speed corresponding to therecording speed mode set in step 62 or 64 stabbly (step 76).

On the other hand, if the recording speed mode of the previouslyrecorded data is identical to that of the video data to be recorded instep 68, then the microcomputer 16 seeks the final portion of thepreviously recorded region based on whether data is inputted from theDSP 28, making a track jump of the optical pick-up device 32 ifnecessary (step 78). Further, the microcomputer 16 allows the clockgenerator 22 to supply a clock signal having a frequency correspondingto the recording speed mode with the formatter 26 (step 80).

Moreover, if the optical disc D does not appear to contain previouslyrecorded data in step 66, then the microcomputer 16 allows the clockgenerator 22 to supply a clock signal having a frequency correspondingto the recording speed mode to formatter 26 by controlling the clockgenerator 22 via the clock frequency change portion 18 (step 118).

After performing the above step 76, 80 or 118, the microcomputer 16allows the optical pick-up device 32 to irradiate a relatively largeenergy of light beam switched under control of the recording portion 34on the surface of the optical disc D by controlling the optical pick-updevice 32, such that the video data VDS is recorded on the optical discD (step 84).

FIG. 8 explains a recorded state of the high resolution video data HVDin the first recording speed mode and the normal video data NVD in thesecond recording speed mode, when those video data are recorded on theoptical disc D by the second embodiment of the present invention. InFIG. 8, a speed DSV of the spindle motor 22 remains at 100 rps untilfirst time t1, at which time the final portion of the high resolutionvideo data HVD in the first recording speed mode recorded on the opticaldisc D is retrieved. At time t1, the optical pick-up device 32 isdisposed on the first position p1, which is the final portion of thehigh resolution video data in the first recording speed mode.

Beginning at the first time t1, the rotation speed of the spindle motor22 decreases slowly until a speed of 50 rps is achieved at second timet2. At the second time t2, the optical pick-up device 32 moves from thefirst position p1, which is the final portion of the high resolutionvideo data in the first recording speed mode, to the second position p2spaced by a certain distance s_(e) from the first position p1. Theoptical pick-up device 32 records the normal video data NVD in thesecond recording speed mode from the second position p2 on the track.Thus, a non-recorded region having a length equal to the movementdistance s_(e) occurs during a rotation speed stabilization period t1-t2of the spindle motor 22 between the high resolution video data HVD inthe first recording speed mode and the normal video data NVD in thesecond recording speed mode.

FIG. 9 is a flow chart for explaining a multi-rate recording methodaccording to the third embodiment of the present invention. The processin FIG. 9 is performed by the microcomputer 16 (shown in FIG. 3).

Referring now to FIG. 9, in step 86, the microcomputer 16 waits until arecord instruction is inputted from the key input portion 14. If therecord instruction is inputted in step 86, then the microcomputer 16sets a record mode flag assigned in a part of register therein, andinputs a transfer rate value of video data from the transfer ratedetector 10 (step 88).

In step 90, the microcomputer 16 decides based on the transfer ratevalue whether the video data VDS on the input/output line 11 correspondsto high resolution video data HVD or normal video data NVD. When thetransfer rate value is 10 Mbps, the microcomputer 16 decides that thehigh resolution video data HVD is being applied to the input/output line11. When the transfer rate value is 5 Mbps, the microcomputer 16 decidesthat the normal video data NVD is being applied to the input/output line11. If it is decided that the high resolution video data HVD is appliedto the input/output line 11 in step 90, then the microcomputer 16 setsthe first recording speed mode flag assigned in a part of registertherein, specifying that the data is to be recorded at a rate of 10 Mbps(step 92). On the other hand, if it is decided that the normal videodata NVD is applied to the input/output line 11 in step 90, then themicrocomputer 16 sets the second recording speed mode flag assigned in apart of register therein instead of the first recording speed mode flag,specifying that the data is to be recorded at a rate of 5 Mbps (step94).

After performing the above step 92 or 94, the microcomputer 16 controlsthe spindle motor 24 via the rotational velocity controller 20 such thatthe spindle motor 24 rotates at a rate corresponding to the recordingspeed mode set in step 92 or 94. At the same time, the microcomputer 16retrieves a table on the lead-in area of optical disc D inputted by wayof the optical pick-up device 32, the recording portion 36, channelmodem 30 and the DSP 28, and decides whether there exists previouslyrecorded data or not (step 96). When a start address and an end addressexist in the table, the microcomputer 16 decides that the data recordedpreviously exists in the optical disc D. Otherwise, when an startaddress and an end address do not exist in the table, the microcomputer16 decides that previously recorded data does not exist in the opticaldisc D. The spindle motor 24 rotates at a rate of 100 rps when the firstrecording speed mode is set in step 92 while rotating at a rate of 50rps when the second recording speed mode is set in step 94.

In step 96, if there is data recorded previously in the optical disc,then the microcomputer 16 compares a logical value of the recordingspeed mode flag with that of the transfer speed mode flag on the table,and decides whether the recording speed mode of the previously recordeddata is identical to that of the data to be recorded (step 98). If thelogical value of the transfer speed mode flag is not identical to thatof the recording speed mode flag, it is judged that the recording speedmode of the previously recorded data is different from that of the videodata to be recorded.

When the recording speed mode of the previously recorded data isdifferent from that of the video data to be recorded in step 98, themicrocomputer 16 allows the spindle motor 24 to be rotated at a speedcorresponding to the recording speed mode of the previously recordeddata by controlling the spindle motor 24 via the rotation velocitycontroller 20. The final portion of the recording region is then soughtbased on whether data is inputted from the DSP 28, with making a trackjump of the optical pick-up device 32 if necessary (step 100). At thistime, if the first recording speed mode was set in step 92, the spindlemotor 24 rotates at a speed of 50 rps; whereas if the second recordingspeed mode was set in step 94, the spindle motor 24 rotates at a speedof 100 rps. Further, the microcomputer 16 inputs an address relative tothe final portion of the previously recorded region from the DSP 28(step 102) , and thereafter allows the clock generator 22 to supply aclock signal having a frequency corresponding to the recording speedmode with the formatter 26 by controlling the clock generator 22 via theclock frequency change portion 18 (step 104). For example, when thefirst recording speed mode is set in step 92, the clock generator 22applies the first clock signal FCS to the formatter 26. Accordingly, thehigh resolution video data on the input/output line 11 is delivered tothe optical pick-up device 32 at a transfer rate of 10 Mbps via thebuffer 12, the formatter 26, the DSP 28, the channel modem 30 and therecording portion 34. Otherwise, when the second recording speed mode isset in step 94, the clock generator 22 applies the second clock signalSCS to the formatter 26. Thus, the normal video data NVD on theinput/output line 11 is transferred into the optical pick-up device 32at a transfer rate of 5 Mbps via the buffer 12, the formatter 26, theDSP 28, the channel modem 30 and the recording portion 34. Themicrocomputer 16 allows the spindle motor 24 to rotate at a speedcorresponding to the recording speed mode set in step 92 or 94 bycontrolling the spindle motor 24 via the rotation velocity controller 20(step 106), and then it waits until the rotation speed of the spindlemotor 24 maintains a speed corresponding to the recording speed mode setin step 92 or 94 stabbly (step 108).

In step 108, when the rotation speed of the spindle motor 24 arrives ata speed corresponding to the recording speed mode set in step 92 or 94,the microcomputer 16 moves the optical pick-up device 32 into theprevious track of the optical disc D (step 110). Next, the microcomputer16 waits until an address relative to the final portion of the recordingregion from the DSP 28 (step 112).

On the other hand, if the recording speed mode of the previouslyrecorded data is identical to that of the video data to be recorded instep 98, then the microcomputer 16 seeks the final portion of thepreviously recorded region based on whether data is inputted from theDSP 28, making a track jump of the optical pick-up device 32 ifnecessary (step 114). Further, the microcomputer 16 allows the clockgenerator 22 to supply a clock signal having a frequency correspondingto the recording speed mode with the formatter 26 (step 116).

Moreover, if the optical disc D does not appear to contain previouslyrecorded data in step 96, then the microcomputer 16 allows the clockgenerator 22 to supply a clock signal having a frequency correspondingto the recording speed mode to formatter 26 by controlling the clockgenerator 22 via the clock frequency change portion 18 (step 118).

After performing the above step 112, 116 or 118, the microcomputer 16allows the optical pick-up device 32 to irradiate a relatively largeenergy of light beam, switched under control of the recording portion34, on the surface of the optical disc D by controlling the opticalpick-up device 32. As such, the video data VDS is recorded on theoptical disc D (step 120).

FIG. 10 explains a recorded state of the high resolution video data HVDin the first recording speed mode and the normal video data NVD in thesecond recording speed mode, when those video data are recorded on theoptical disc D by the third embodiment of the present invention. In FIG.10, a speed DSV of the spindle motor 22 remains at 100 rps until firsttime t1, when the final portion of the high resolution video data HVD inthe first recording speed mode recorded on the optical disc D isretrieved. At time t1, the optical pick-up device 32 is disposed on theposition p2, which is the position of the final high resolution videodata recorded in the first recording speed mode.

Beginning at the first time ti, the rotation speed DSV of the spindlemotor 22 decreases slowly until a speed of 50 rps is achieved at secondtime t2. Between first time t1 and second time t2, the optical pick-updevice 32 is moved from the position p2, which corresponds to the finalposition of the high resolution video data in the first recording speedmode, to the position p1 spaced by a certain distance s_(e) from theposition p2. Therefore, to avoid a null space between positions p1 andp2, the optical pick-up device 31 is moved backward by a distance s_(e)corresponding to the movement experienced during the change in spindlemotor speed. In this manner, the optical pick-up device 31 is returnedfrom position p2 to position p1.

If the optical pick-up device 32 delays recording the normal video dataNVD in the second recording speed mode until the third time t3, theoptical pick-up device 32 must also be moved by a certain distance s_(b)corresponding to the movement ordinarily experienced by the opticalpick-up device 32 during that time delay, namely a track jump from theposition p2 on the track to the position p3 preceding positions p1 andp2. It is also possible to perform a single jump as shown in FIG. 10,corresponding to a combination of distances s_(c) and S_(b).

In the manner described above, in the second recording speed mode, thenormal video data NVD is recorded after the final portion of the highresolution video data HVD such that a non-recorded null space region isavoided.

According to this second embodiment, null spaces can be avoided with asingle jump, regardless of whether delays are experienced for speedchanges. For instance, when delays are experienced for speed changes,the process is performed as described above. When such delays are notexperienced, the same process is performed, but the jump correspondingto distance s_(e) is not necessary.

That is, in either case, to avoid null data regions, the presentinvention performs a reverse jump and a recording operation when theoptical disc is rotated at the speed corresponding to the transfer rateof the high resolution video data which is higher than the normal videodata. In other words, the present invention initially allows therotation speed of the optical disc to be maintained at the speedcorresponding to the transfer rate of the high resolution video data.The transfer rate of input video data to be recorded is detected using atransfer speed detector 10 (shown in FIG. 3). The input video data isidentified as any one of the normal and high resolution video dataaccording to the transfer rate of the input video data. If the transferrate detected by the input 10 is the first transfer rate (i.e., theinput video data is the normal video data), the pick-up is reverselyjumped each time a constant amount of normal video data have beenrecorded on the optical disc.

In greater detail, the pick-up is positioned at the end point ofpreviously recorded data (or the start point of the data area if no datahas been previously recorded), and a constant amount of the normal videodata is recorded on an otherwise null data region following the endpoint of the previously recorded data area by a constant distance.

After the constant amount of the normal video data has been recorded onthe otherwise null data region, an amount of normal video data to berecorded next must be prepared before further recording can beperformed. To provide time for the preparation of the this data withoutcreating a null data region, the pick-up jumps reversely at least onetrack. This is demonstrated by FIG. 10, where a constant amount ofnormal video data is recorded on the otherwise null data region betweenpositions p1 and p2, and the pick-up thereafter jumps reversely toposition p3 to provide time for the preparation of additional normalvideo data to be recorded after position p1. The jump can be greaterthan the constant amount of normal video data being recorded, as shown,or less. While the pick-up moves from the new position (e.g., p3) to anew start point (e.g., p2) of the null data area, the next normal videodata to be recorded is pre pared. The prepared normal video data is thenrecorded on the otherwise null data region following the new start pointof the null data area.

In this manner, the present invention successively and repeatedlyperforms the reverse jumping and the recording operations when thenormal video data having a low transfer data is recorded on the opticaldisc rotating at the speed corresponding to a high transfer rate,thereby preventing the generation of the null data on the optical disc.As a result, the present invention effectively uses the recordingcapacity of the optical disc.

As described above, according to a multi-rate recording method andapparatus of the present invention, the rotation velocity of the opticaldisc and the processing speed of data can be controlled in accordancewith the transfer rate of the data to be recorded such that theunnecessary data is not recorded on the optical disc. As a result, themulti-rate recording method and apparatus according to the presentinvention provides an advantage in that it can improve recordingefficiency of optical disc and the recording time thereof dramatically.

Although the present invention has been described by the preferredembodiments illustrated in drawings hereinbefore, it is apparent fromthe above description to those ordinarily skilled in the art thatvarious changes and modifications of the invention are possible withoutdeparting from the spirit thereof. For instance, it may be suggestedthat the buffer shown in FIG. 3 is disposed between the formatter 26 andthe DSP 28 or between the DSP 28 or the channel modem 30 to supply theclock signal generated at the clock generator 22 with the DSP 28 or thechannel modem 30, thereby controlling the processing speed of videodata. Also, while the present invention has been described to be limitedto the video data, it is to be understood that it may be applied toother data such as text data and packet data, etc. Accordingly, thescope of the invention should be determined not by the embodimentsillustrated and described, but by the appended claims and theirequivalents.

What is claimed is:
 1. A multi-rate optical disc recording method forrecording a digital signal from a digital signal source on an opticaldisc, comprising: controlling the rotating speed of the optical disc tomaintain a recording speed at a specific value corresponding to aspecific transfer rate; determining whether the transfer rate of thedigital signal to be recorded is lower than the specific transfer rate;recording the digital signal on the optical disc by performing arecording apparatus that includes moving a pick-up device relative tothe disc in a direction opposite a recording direction if the transferrate of the digital signal is determined to be lower than the specifictransfer rate.
 2. The method as claimed in claim 1, wherein therecording comprises: performing a normal recording operation when thetransfer rate of the digital signal to be recorded corresponds to thespecific transfer rate.
 3. The method as claimed in claim 2, where thenormal pick-up device is performed only when the transfer rate of thedigital signal to be recorded is equal to the specific transfer rate. 4.The method as claimed in claim 2, wherein the digital signal to berecorded on the optical disc is constantly maintained in the transferrate.
 5. The method as claimed in claim 2, wherein the digital signalsource is a broadcasting station.
 6. The method as claimed in claim 2,wherein the digital signal source is another information storage device.7. A multi-rate optical disc recording method for recording a digitalsignal from a digital signal source on an optical disc, comprising:controlling the rotating speed of the optical disc to maintain aconstant recording speed corresponding to a specific transfer rate, thespecific transfer rate being set previously based on any one of at leasttwo potential transfer rates of the digital signal; determining whethera transfer rate of the digital signal to be recorded corresponds to thespecific transfer rate; recording the digital signal on the optical discby performing a recording operation that includes repeatedly moving apick-up device relative to the disc in a direction opposite a recordingdirection if the transfer rate of the digital signal is determined notto correspond to the specific transfer rate.
 8. The method as claimed inclaim 7, wherein the specific transfer rate is a highest rate among theat least two potential transfer rates of the digital signal.
 9. Themethod as claimed in claim 8, wherein the recording comprises:performing a normal recording operation when the transfer rate of thedigital signal to be recorded corresponds to the specific transfer rate.10. The method as claimed in claim 8, wherein the digital signal to berecorded on the optical disc is constantly maintained in the transferrate.
 11. The method as claimed in claim 8, wherein the digital signalsource is a broadcasting station.
 12. The method as claimed in claim 8,wherein the digital signal source is another information storage device.13. A method for recording digital data on a recording medium,comprising: determining a transfer rate by which digital data is beingreceived; comparing the transfer rate of the digital data to a desiredrecording rate; and recording the digital data at a position on therecording medium that is identified by moving a pick-up device relativeto the recording medium in a direction opposite the recording directionbased on the comparison of the transfer rate and the desired recordingrate.
 14. The method as claimed in claim 13, wherein the digital data isrecorded at a position that is identified by moving the pick-up devicerelative to the recording medium in the direction opposite the recordingdirection when the transfer rate is determined to be different than thedesired recording rate.
 15. The method as claimed in claim 13, whereinthe digital data is recorded at a position that is identified by movingthe pick-up device relative to the recording medium in the directionopposite the recording direction when the transfer rate is determined tobe lower than the desired recording rate.
 16. The method as claimed inclaim 13, wherein the recording comprises: moving the pick-up devicefrom a position beyond a target recording position to a position thatprecedes the target recording position; and recording the digital datawhen the pick-up device returns to the target recording position. 17.The method as claimed in claim 16, wherein digital data is prepared tobe subsequently recorded while the pick-up device returns from theposition that precedes the target recording position to the targetrecording position.
 18. The method as claimed in claim 17, wherein themovement amount of the recording head is related to the amount ofprocessing necessary to prepare digital data to be subsequentlyrecorded.
 19. The method as claimed in claim 13, further comprising:determining the desired recording rate based on the recording medium.20. The method as claimed in claim 13, further comprising: determiningthe desired recording rate based on information previously recorded onthe recording medium.